DECT ULE Tutorial
This DECT ULE Tutorial covers DECT ULE system basics, DECT ULE specifications or features, DECT ULE protocol layers viz. physical, MAC, DLC, Network. It also mentions applications, advantages (merits) and comparison of DECT ULE with other wireless technologies such as zigbee, zwave, bluetooth etc.
About DECT ULE: DECT ULE is the new upgraded version of legacy DECT technology used as cordless telephony. DECT ULE (Ultra Low Energy) is mainly targetted for M2M, Home automation, WSN and security applications in addition to support for voice services.
It is maintained and managed by DECT forum, ETSI and ULE Alliance group of companies. The DECT ULE devices support long range and moderate data rates. The power consumption is very low and will have low latency.
DECT ULE System features
Following are the silent features of DECT ULE system:
• Supports maximum coverage of upto 600 meters in outdoor and 70 meters in indoor environments.
• It operates in frequency band of 1.8GHz in Europe and 1.9GHz in US with channel spacing of 1.728 MHz.
• It supports data rate of 1 Mbps.
• Due to very less power consumption and larger sleep period (about 20sec), battery will last for 5 to 10 years.
• It provides high security of information due to use of 128 bit size of key in AES algorithm.
• It uses TDD/TDMA/FDMA access techniques.
• Supports variable packet size from 32 to 256 bytes.
• Supports latency of less than 100 ms for node to base and base to node transfer of ULE datagram of size 64 bytes.
• Supports maximum nodes of more than 400
• It enables simultaneous use of voice and data services.
• It supports one hop star network topology.
DECT ULE Protocol stack
Fig:1 DECT ULE Protocol Stack
DECT ULE Protocol Stack consists of following layers.
• Physical Layer: It defines physical channels across band which are used for different functions. It uses FDMA, TDMA and TDD modes for efficient time/frequency resource utilization.
It uses 24 time slots in 10ms duration on each of the carrier. Each time slot carries packet which is composed of synchronization field, control information, service and error control.
• MAC Layer: This layer performs functions such as selection of physical channels based on functionality, establishment and release of connections, multiplexing and demultiplexing of control information along with upper layer information as well as error control information into(or from) fixed size packets.
• DLC (Data Link Control) Layer: It provides high level of data integrity along with MAC layer. There are two planes supported in DECT ULE viz. C-plane and U-plane. C-Plane It is common to all applications. C-plane provides reliable transmission of control/signalling and limited user traffic. U-plane provides support for speech and data transmission in CS (Circuit Switched) and PS (Packet Switched) mode respectively. There are many other services supported by U-plane. DLC layer is responsible for routing of C-plane and U-plane information data to appropriate connections.
• Network Layer: It operates between peers with exchange of messages. The messages are used for establishment as well as maintenance/release of calls.
• IWU (Interworking Unit): It interfaces DECT air interface with other networks as well as line interfaces. This layer lies between DECT protocol stack and other outside functional layers (if any).
DECT ULE Applications
Following are the applications of DECT ULE System:
• Monitoring and Control in Home automation
• M2M (Machine to Machine) Communication
• Security (common devices include ULE security camera and ULE door phone)
• Internet using DECT ULE enabled broadband gateway
• Fire alarm ( using DECT ULE Smoke detector )
• DECT handset and fixed unit for voice/data applications
• Creates WSN (Wireless Sensor Network) by installing actuators/sensors in buildings across the city and rural areas.
• It supports VOIP applications.
DECT ULE Advantages
Following are the advantages of DECT ULE technology:
• It is long established and stable technology since 1987.
• As it is open standard, products from multiple vendors are interoperable.
• It operates in interference free frequency bands.
• It provides very good security and authentication features.
• It achieves very long range and can penetrate buildings by controlling transmission power.
• It supports high QoS Voice and wide-band voice (CAT-iq) applications.
• Easy installation and commissioning.
• DECT ULE uses same legacy DECT core technology and hence devices are available at very cheap and affordable rates.
• It has very less energy consumption (in µA) and hence supports longer battery life.
• It supports lower latency which is useful for WSN sensors requiring very fast feedback.
• It is backward compatible with legacy DECT based devices.
Comparison between DECT ULE and Other Wireless Standards
Following table summarizes comparison between DECT ULE with other wireless standards such as zigbee, zwave and bluetooth.
|Coverage Distance||from 70 meters (indoor) to 600 meters (outdoor)||10 meters||10 to 100 meters||30 to 65 meters|
|Frequency||1.8 GHz , 1.9 GHz||2.4 GHz||868/915 MHz, 2450 MHz||sub 1GHz band|
|Data rate||Higher data rate, 1Mbps||1 Mbps||250 Kbps (2450MHz band), 20 to 40 Kbps (868/915 MHz)||40 Kbps|
|Applications||Cordless telephony, M2M, home automation, security||cellphone related adhoc communications||Low Power Wireless Networks||Home automation|
Legacy DECT basic tutorial
Difference between DECT and DECT ULE
Difference between TDD and FDD
TDMA-This page covers TDMA basics,types of TDMA and mention disadvantages.
FDMA-versus-TDMA-versus-CDMA-This page covers comparison between FDMA,TDMA and CDMA access techniques.
FDM-versus-TDM-This page covers compares FDM and TDM multiplexing techniques.